Tumors of colon and appendix 1/31

Question 1

hyperplastic polyps

Answer 1

due to delayed shedding of surface epithelium

most common in rectosigmoid

no neoplastic potential

Question 2

inflammatory polyp

Answer 2

example is solitary rectal ulcer syndrome

due to impaired relaxation of anorectal sphincter

presents with rectal bleeding, mucus and inflammatory lesions of anterior wall–> polyp

Question 3

Cowden syndrome+ BRR syndrome

Answer 3

AD hamartomatous polyps

loss of function mutation in PTEN

Cowden=microcephaly, hamartomatous polyps, benign skin tumor

increased risk of breast, follicular thyroid+endometrial CA

Question 4

Cronkhite-Canada syndrome

Answer 4

not hereditary, seen over 50

diarrhea, weight loss, abd pain, weakness, nail atrophy and splitting, hair loss, skin discoloration

see hamartomatous polyps of stomach, SI and colorectum

unknown cause

Question 5

Pathognomonic mucocutaneous features of Cowden syndrom

Answer 5

Trichilemmomas on nape of neck

palmar keratosis

perioral papillomatous papules and nasal polyposis

gastric hamartomas

Question 6

types of adenomas

Answer 6

Tubular= majority and most common

tubulovillous

villous

sessile serrated= premalignant

carcinoma risk= size, architecture, amount of dysplasia

Question 7

If adenoma reaches muscolaris mucosae

Answer 7

can still be resected and no risk of mets, but beyond that there is increased risk of mets

Question 8

APC/B-catenin pathway

Answer 8

1) Normal colon= germline or somatic mutations of cancer suppressor genes (first hit), (APC)
2) Mucosa at risk= methylation abnormalities, inactivation of normal alleles (second hit), (APC/ beta-catenin)
3) Adenomas= a)protooncogene mutations, (KRAS). b) homozygous loss of additional cancer suppressor genes and overexpression of COX2, (p53+LOH)
4) Carcinoma= additional mutations and gross chromosomal alterations, (telomerase and many genes)

Question 9

Microsatellite instability

Answer 9

1) Normal= germline or somatic mutations of mismatch repair genes–> alteration of second allele by LOH, mutation or promotor methylation–>
2) sessile serrated adenoma= microsatellite instability–> accumulated mutations in genes that regulate growth, differentiation and apoptosis–> CA

Question 10

APC function

Answer 10

regulation of beta catenin induced signaling

regulation of cell adhesion

regulation of cell migration via microtubule interaction

Question 11

Amsterdam criteria for HNPCC

Answer 11

3 or more members of in at least 2 successive generations must have colorectal CA

At least one case diagnosed before age of 50

one of affected members should be first degree relative of the other 2